1. Field of the Invention
The present invention relates to an optical disk for storing digital data of multimedia data including audio information and moving image information that are associated with each other, as well as an apparatus and a method for reproducing the same.
2. Description of the Related Art
Conventionally, CDs (compact disks) and LDs (laser disks) are -known as optical disks for storing and reproducing audio Information and/or moving image information.
A CD is an optical disk having a diameter of 12 cm. A CD carries audio information stored thereon which has been quantized by using a linear PCM method. CDs are widely prevalent as a storage medium for music-oriented applications.
An LD is an optical disk having a diameter of 30 cm. An LD carries moving image information stored thereon in the form of analog signals. LDs are widely prevalent as a storage medium for image-oriented applications such as movies.
In addition to such uses, applications which cannot be distinguished to be either simply music-oriented or image-oriented have emerged, e.g., operas and the recently-evolved music clips (i.e., music accompanied by images).
Herein, those uses which cannot be distinguished as either music-oriented or image-oriented will be referred to as being directed to "image-accompanied music".
In the case of applications of image-accompanied music, it is difficult to know which mode of viewing/listening a user may desire because one user may wish to only listen to the music without viewing the images, while another may wish to enjoy both the music and the images. It is also possible for the same user to desire variable modes of viewing/listening depending on each situation. For example, a user may wish to only listen to music in the case where the user runs an image-accompanied music application on a portable reproduction apparatus while moving around or on a reproduction apparatus mounted in an automobile, but the same user may wish to enjoy both the music and the images when running the image-accompanied music application on a non-portable reproduction apparatus at home.
However, in the case of playback of only the audio information of an image-accompanied music application, merely omitting the image information reproduced from the Image-accompanied music application from display may result in an awkward reproduction of those voices or sounds which would only be meaningful when reproduced along with images, e.g., the voices and sounds of an interview in an music clip.
Furthermore, merely omitting from display the image information reproduced from the image-accompanied music application may result in a malfunctioning of the reproduction apparatus due to the omission of the images. For example, in the case where an image menu is omitted from display, it is. possible for the application to remain waiting for an input responsive to the undisplayed image menu.
Furthermore, there may be a desire to enjoy higher-quality voices and sounds during audio reproduction than during video reproduction.